If you use shopkick or Foursquare, you already know: Online and offline worlds are colliding as consumers become more comfortable with networks, apps and mobile devices. And as for the companies making it their business to link up the two worlds, they're reaping some serious benefits.

Take, for instance, Los Angeles-based ShareSquare, which uses quick response, or QR, codes (those small black-and-white dotted squares showing up on more and more product packaging and ads) to help convert a moment of consumer discovery into one of action.

QR codes have been around for years, admits founder and CEO Matthias Galica, a graduate of the 2010 Founder Institute startup mentorship program in Silicon Valley. But ShareSquare is making headway where others have failed because musicians--the company's target vertical--are scrappy early adopters.

In just six months, about 10,000 users have already registered with the service, which helps artists connect with fans who scan codes with smartphones to get access to contests, exclusive music videos, song downloads, Facebook and Twitter feeds--and soon, tickets, albums and other merchandise. The paid product ($99 or $499 a month) lets users earn revenue by publishing ads and displaying content on a navigation-friendly mobile site.

"We're reaching a social tipping point, where an average Joe will see a QR code on the street and know exactly what to do with it," says Galica, his confidence boosted by a successful pilot campaign with Hannah Montana's Mitchel Musso; a great showing at SXSW in Austin, Texas; and talks with big media companies like National Geographic and NBC Universal about cross-promoting content on different platforms. Other items on Galica's to-do list: a second round of funding, hiring at least six more employees and pursuing an acquisition strategy to bring in a bigger user base.

Arguably, the most exciting piece is what ShareSquare's real-time analytics platform means for outdoor advertising metrics. "If you can get enough people to start clicking in the real world, engaging with ads, you quickly start to see useful trends like where your customers really are, or what the hottest concert will be," Galica says. "That's just a taste."

More 'Connected' Brilliance

Bumped.in Wait, commuting can be fun? Users of this app browse for people near them to find common interests and meet new travel buddies.

CitySourced This civic mobile engagement app lets people report and share photos of community issues they want to see addressed (like graffiti or potholes).

Color This free app takes pictures, videos and recorded conversations from users' smartphones and uploads them to a shared community album.

Groundspeak All about outdoor play using location-based technology, this company deployed Geocaching.com, the first official site for treasure-hunting hobbyists.

Grubwithus Bringing people together through food, this site lets users pick a restaurant, reserve a seat, pay in advance and make new friends over a good meal. Bon appétit.

LifeKraze Live a little: Do something active, post updates on LifeKraze and get followers to award you points that can be redeemed for active lifestyle prizes.

Meet Gatsby This site introduces people with shared interests when they check in on Foursquare or Facebook. Now virtual friends can connect in real life.

stickybits Scan the barcode of a product to check out its reviews, tweets, videos and pictures and get points redeemable for discounts and free stuff.

StreetSpark Through social matching and GPS, users get alerts on their smartphones when they cross paths with potential flames.